Electrical discharge device



Jan. 23, 1940. v GERMER 2,187,736

ELECTRICAL DISCHARGE DEVICE Filed April 13, 193'? i is. i

INVENTOR EDMUND GERMER N EYS I AT'To Patented Jan. 23, 1940 PATENT OFFIICE ELECTRICAL DISCHARGE DEVICE EdmundGermer, Berlin Wannsee, Germany Application April 13,

7 Claims.

prior copending application, Serial No. 5001346,

filed December 5,1930, and m the use of such devices under various conditions met with in practical use difiiculty has been experienced, due

I to the intense loading of the arc and to intense localization of the heating from the arc which occurs under certain conditions ofconvection. I It is an object of my present lnventionito-provide such a discharge device in which injury to the envelope will be avoided even if the wall of the envelope is made of glasswhich would be injured by the localized heating (it thedischarge in the high pressure are lampnow. in use.

According to my'inventionthe parts o envelope wall which are subjected to localized heating are designed to provide increased heat dissipation, e. g., by convection, radiation, etc.

In the accompanying drawing. Iuhave shown several embodiments of my invention and below I have suggested various modifications thereof. It should be understood, however, that these are not intended tobe exhaustive or limiting offthe invention, but onthe contrary are given in order that others skilled in the art may fully understand the invention and the principles thereof so that they may be able to adapt it and modify it and to embody it in numerous other forms each as may be best adapted to the particular conditions and requirements of any intended use.

-' In the drawing:

Fig. 1 shows, partly in elevation and partly in section, a lamp suitable for commercial use which embodies my invention;

Fig. 2 is a cross sectional view taken on line 2-2 of Fig. l;

Fig. 3 is a cross section taken on line 33 of Fig. 1;

Fig. 4 is a view in side elevation of a lamp designed for horizontal burning;

Fig. 5 is a cross sectional view of a lamp similar to that shown in Fig. 4, but of modified shape;

and

Fig. 6 is a cross s intended for horizontal burning.

Referring first to Fig. 1, I have shown there a lamp similar to the high pressure mercury vapor lamps which are now in common use, in that In Germany February 22, 1936 r the" ectional view of another lamp 1937, Serial No. 136,539

there is an inner envelope l0 provided with electrodes (not shown) at oppositeendsmountedon lead-in wires ll and l2 sealed through the ends of the envelope l0. Around this envelope, in

order to protect it from unregulated convectionl currents or draughts, is the jacket l3 of glass or other light permeable material; and to one end of this jacket is cemented a connector base I,

e. g., 'of the ordinary .Ediswan Mogul type. A resilient frame J5 is mounted within the jacket 10 (3 to hold the envelope 1 0 in place and serves also to conduct the current for the arc to the farther lead-in wire l2.

-To this extent the lamp is similar to others which are now in use. The form of the envelope 5 If], however, and the form of the frame l5 are improved in the construction shown in this drawing as compared with similar lamps known prior to my invention. The frame is more fully described and claimed in a co-pen of F. H. A. Brandt.

In the upper part of the envelope ill I have provided corrugations l6 which increase gradually in depth from near the middle of the tube to. its upper end. The jacket I3 isfilled with a-convection gas, e. g., atmospheric. air at' approxi mately 1 atmosphere pressure, and these corrugav tions I 6 provide 'channels in which the convec tion'currents flow smoothly and rapidly in contactwith the glass. Thus in the upper portion of the envelope where the convection currents within the envelope tend to concentratethe heat from the arc the heat dissipating capacity of the envelope is correspondingly increased.

It is advantageous to form the corrugations as shown, for example, in Fig. 2, with the extended folds narrower than the re-entrant folds. Thus the part of the folded wall which is nearest to the center of the tube is exposed to' a convectionstream sufficiently broad to keep these portions 40 cooled. The outwardly extended folds, however, must not be so narrow as toallow excessive cooling of their outermost v parts which would cause condensation of the metal vapor when such is used Within .the tube.

A similar desirable effect can be obtained by corrugations extending transversely around the tube instead of longitudinally. Where the lamp is to be burned in vertical position, however, this is not to be recommended because the parts most strongly heated on the interior are least exposed to the convection currents on the exterior. When, however, the tube is to be burned in horizontal position, such transverse corrugations are advantageous for the same reason.- In such case, 55

ding application 20 however, it is not necessary or desirable to have the corrugations extend completely around the tube, but on the contrary they are preferably extended with gradually increasing depth from about the middle of the tube to the top. This I have shown, for example, in Fig. 4, in which corrugations of increasing depth are provided beginning near the ends in which transverse corrugations of this type are provided beginning near the ends and increasing respectively in depth to the center of the tube where the upper wall is most strongly heated due to the upward curve of the are between the electrodes.

In Fig. 5, I-have shown in cross section a tube of particularly advantageous form. In this case'the tube is streamlined in cross section. has two-fold advantage. In the first place, the streamline permits the convection currents to flow more rapidly and smoothly in contact with the glass of the tube and thus, makes for increased heat-exchange efliciency. In the second place, the departure from the circular form increases the area in which the inner and outer gases are in convection contact with the wall. Another advantage is that the gradual increase in the upward extension of the tube wall toward the center of its length, carries it above the arc path which would be necessary in a simple cylindrical tube.

In Fig. 6, I have shown in cross section a streamlined tube which attains advantages of streamlining, but without the increased area due to corrugations.

This application is a continuation in part of my application Serial No. 119,405, filed December 24, 1936, for Electrical discharge devices.

What I claim is:

1. A gaseous electrical discharge device comprising spaced arcing electrodes, an envelope closely surrounding a discharge path between the electrodes, a material within the envelope adapted to provide a gaseous atmosphere for the discharge, and a cooling fluid outside said envelope which is characterized by the envelope having upwardly directed channels near its top for flow of convection gases and giving it a greater average convection area per unit length near its top than near its bottom, whereby to counteract by increased cooling the tendency of convection in the discharge carrying gas to concentrate heat from the discharge in the upper'part of the envelope. 2. A horizontal burning high pressure arc burner o! the type having spaced arcing electrodes, an envelope closely surrounding an arc path between them, a material within the envelope adapted to provide an atmosphere for the are of pressure sufilcient to give it the form of a luminous cord constricted away fromthe wall of the envelope which is characterized by the upper part of the envelope being transversely corrugated at least in the portion between the electrodes where the arc tends to'approach said upper'part.

tween them, a material within the envelope. adapted to provide an atmosphere for the are sufllcient to give it the form of a luminous cord constricted away-from thewall of the envelope which is characterized by the envelope being streamlined in cross sectional shape and exposed to a convection fluid. whereby the upper part of said convection surface is in more efficient heatexchange contact with the convection gas than the corresponding part of a circular tube of equal cross sectional area.

5. A high pressure are burner of the type having spaced arcing electrodes, an envelope closely surrounding an arc path between them, a mate rial within the envelopeadapted to provide an atmosphereiorthe arc of pressuresufficient to give it the form of a luminous cord constricted away from the wall of the envelope which is characterized bythe upper part of the envelope being corrugated.

6. A high pressure are discharge device as definedin claim 5, in which the envelope at least at the top of the corrugations is streamlined in sectional shape taken parallel to the corrugations.

7. A high pressure are burner of the type having spaced arcing electrodes, an envelope closely surrounding an arc path between them, a material within the envelope adapted to provide an atmosphere for thearc of pressure sufllcient to give it the form of a luminous cord constricted away from the wall of the envelope which is characterized by the envelope being streamlined in sectional shape taken parallel to the convection currents and exposed to a convection fluid in the direction of said streamlining, whereby the upper part of said convection surface is in more efiicient heatexchange contact with the convection gas than would be the corresponding part of a spherical tube of equal cross sectional area.

EDMUND GERJVIER. 

